Reactive Metal Diffusion Barrier for IC Interconnects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As integrated circuit dimensions decrease, electromigration failures and increased metal line resistance become issues due to copper diffusion into semiconductor and dielectric materials, necessitating a diffusion barrier that minimizes volume while maximizing copper fill volume to reduce electrical resistance.
Innovation Solution
A diffusion barrier is formed using a layer of reactive metals like Co, Ru, Mo, or W, which thermally reacts with dielectric materials to create a thin, low-resistivity barrier that prevents copper diffusion, allowing for maximum copper fill volume and reduced electrical resistance in interconnect structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diffusion barrier material is used to prevent copper diffusion, then copper diffusion is prevented, but the electrical resistance increases due to the higher resistance of the barrier material
Solution Approach 1:
The patent changes the material parameter from conventional diffusion barrier materials (Ta, TaN, WN) to reactive metal materials (Co, Ru, Mo, W, Ir) that form compounds with dielectric materials. This material substitution reduces the thickness of the diffusion barrier while maintaining its protective function, thereby reducing the electrical resistance in the interconnect structure.
2Loss of energy
If the thickness of the diffusion barrier is reduced to maximize copper fill volume, then the electrical resistance decreases, but the diffusion barrier may become ineffective at preventing copper diffusion
Solution Approach 1:
The patent changes the material composition parameter by using reactive metals that form compounds with dielectric materials. These compound-forming materials achieve effective diffusion barrier functionality at reduced thicknesses compared to conventional materials, thus maintaining diffusion prevention capability while minimizing resistance.
Solution Approach 2:
The reactive metal materials used in the patent form compound structures with dielectric materials through thermal reaction. This composite material approach creates a diffusion barrier that is both thin and highly effective, resolving the contradiction between barrier thickness and diffusion prevention capability.
3Reliability
If conventional diffusion barrier materials are used, then copper diffusion is prevented, but the volume of copper fill is reduced due to the larger required barrier thickness
Solution Approach 1:
The patent changes the material parameter from conventional barrier materials to reactive metals that form compounds with dielectrics. This enables the diffusion barrier to be made much thinner, thereby maximizing the copper fill volume in the interconnect structure while maintaining effective diffusion prevention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The reactive metal diffusion barrier effectively prevents copper diffusion, maximizing copper volume and minimizing electrical resistance in interconnect structures, thereby enhancing the performance and reliability of integrated circuits.
Implementation Method 1
thermally reacting at least a portion of the metallic layer with at least a portion of the dielectric material to form a diffusion barrier primarily containing a compound of the reactive metal from the metallic layer and the dielectric reactant element from the dielectric material
Data Source
AI summary
An interconnect structure for an integrated circuit and method of forming the interconnect structure. The method includes depositing a metallic layer containing a reactive metal in an interconnect opening formed within a dielectric material containing a dielectric reactant element, thermally reacting at least a portion of the metallic layer with at least a portion of the dielectric material to form a diffusion barrier primarily containing a compound of the reactive metal from the metallic layer and the dielectric reactant element from the dielectric material, and filling the interconnect opening with Cu metal, where the diffusion barrier surrounds the Cu metal within the opening. The reactive metal can be Co, Ru, Mo, W, or Ir, or a combination thereof. The interconnect opening can be a trench, a via, or a dual damascene opening.